For the nucleic acid analysis e.g. of white blood cells from whole blood to answer human genomic questions, the cells must firstly be broken up in a sample preparation step and the DNAs thereby released must subsequently be isolated. It is in this case necessary to remove blood constituents such as hemoglobin, immunoglobulins and lactoferrin, which could inhibit a subsequent PCR.
In the laboratory, these working steps are carried out according to a sufficiently well-known prior art. In particular, the DNAs are bound to so-called magnet beads for isolation. The magnet beads with the DNA can be transported in a controlled way via external magnetic fields and enriched at predetermined positions. The isolated DNA can subsequently be eluted from the beads or used together with the beads (as a DNA/bead complex) for the PCR (Polymerase Chain Reaction).
According to the prior art, the isolated genomic DNA is added to a PCR reagent solution (polymerase, primer, nucleotides, buffer, auxiliaries) and the entire batch is subjected to thermocycling which is suitable for the PCR.
Conduct of the latter process is contingent on the provision of laboratory equipment such as PCR equipment (thermocycler), so-called Eppendorf reaction vessels, pipetting equipment, cooling containers for reagents, and must be carried out by trained personnel while complying with safety rules (infection risk, waste disposal . . . ). A plurality of volumetric, accurate dosings (pipettings) of reagent solutions must be carried out. These working steps are also time-consuming.
EP 0 572 057 A1 discloses a composition for PCR reagents, in which the reagents are covered with a meltable material in order to prevent undesired reactions. The way in which false reactions can be avoided before the PCR per se is furthermore described in detail by the publication in “Nucleic Acids Research”, Vol. 20, No. 7, pages 1717 to 1723. So-called hot-start PCR, which is based on an elevated starting temperature, is moreover described in [www.bioexpress.com].
The processes described above are suitable in principle for laboratory analysis. U.S. 2002/0022261 A1 moreover describes a system for miniaturized genetic analysis and associated operating processes, in which a cartridge with at least one input to a channel is used. Disintegration of cells for a subsequent PCR is intended to take place in the channel. For the PCR, reagents relevant thereto are provided.
DNA analysis devices are known from WO 02/072262 A1, U.S. Pat. No. 5,550,044 A, U.S. Pat. No. 5,599,660 A and U.S. Pat. No. 5,972,386 A. PCR methods are furthermore described in the publications PCR Met. Appl. Vol. 4, No. 3, pages 191 to 194 and Nucl. Acid Research Res., Vol. 21, pages 2959 to 2960.